Dextran resinous product



Patented July 15, 1941 DEXTRAN RESINOUS PRODUCT Grant L. Stahly and Warner W. Carlson, Columbus, Ohio, assignors to Commonwealth Engineering Corporation, Wilmington, Del., a corporation of Delaware v No Drawing. Original application July 29, 1937, Serial No. 156,426. Divided and this application November 4, 1938, Serial No. 238,854

1 Claim. (01. 260-209) This invention relates to the production of polysaccharide materials by the action of various micro-organisms on suitable culture media, and to processes for converting these polysacperlodic addition of alkali to the fermenting media or by using an excess of calcium carbonate in the media. After inoculation the cultures are incubated at the temperatures most charides into their ether, mixed ether, ester, 5 favorable to the growth of the micro-organism mixed ester or mixed ether-ester derivatives. being used. For one of the pref rred f rm It is the object of thi i v nti t produce Leuconostoc mesenterioides, this temperature is polysaccharide materials by the action of vararound 25 degrees The P ogress of the ferious micro-organisms on suitable culture media mentation may be followed by periodically removand in particular to produce dextr n; a d t ing samples of the fermenting culture media and thereafter subject the polysaccharide materials pr ipitatin h p lys hari e c ntained in such as dextran to a process of etherification or them by the addition of three to five times esterification either while the materials are in their u e of alcohole p e p Po ythe culture media or after separation therefrom s c haride may then be weighed. When a maxso as to produce the new products of resinous l5 imum of polysaccharide has been formed the culcharacter such as the benzyl ether of dextran, ture media are ready for the etherification or the butyl ether or dextran, etc. esterification processes. The length of time nece po ysaccharides are produced by inocuessary for the maximum of polysaccharide to be lating media containing sucrose, nitrogenous f rm will v ry with the or ni m employe compounds and various salts with bacteria, of the temperature of incubation, the concentraknown genus and species. These bacteria may tion of sucrose and other factors. be placed in one of two groupings, those that The polysaccharide may be isolated from the produce polysaccharides known a levans, or solution by precipitation with alcohol or acetone. those that produce the polysaccharides k ow Preferably the reaction of the fermented medium as dextrans. The two types of polysaccharides is first adjusted to the neutral point to lessen are distinguished from one another by the fact the possibility of hydro y of the po ys c a d that on hydrolysis with acids or enzymes, th and the solution th n concentrated under redextrans yield only dextrose while the levans d d P s u e at a temperature of 40 o 50 yield only levulose. As specific examples, BaciZ-' grees C. to app o y O eo t s Ori lus mesentericus, B. subtilz's, B. megatherium, 0 volume. The solution is then poure W St Pseudomonas primi, Ps. prunicola or Ps. phaseoli ring, into three to five times its volume of alcomay be employed for the production of the levan hol or acetone. The po ysaccharide may be p type of polysaccharide, whil Leuconosto e cipltated directly from the fermented culture terioides or L. dezrtranicum ma be used for media by the addition of alcohol or acetone, but the production of the dextran type. it is then necessary to use a considerably larger The culture media employed should prefera u f the p pita in a ntably contain some sucrose; this can be either rer e p p ation" of t e ether and este'r fined or crude sucrose, molasses or any imilar derivatives of these polysaccharides it is not necsucrose containing material. Nitrogen may be essary that they first be isolated from the culture added in the form f commercial t n beef 40 media in which they were formed. Instead the extract or other nitrogen containing material. necessary reagents y be added directly to e If molasses is used as the sucrose source, nifermented media, a after c mp et of the trogenous compounds in fli i i; quantity are reaction, theether, ester, or mixed ether-ester present in it so that none need be add d, salt derivatives can be recovered from the mixture, such as dipqtagsium phosphate and sodium 1 either by a simple mechanical process in case ride are also added, As a pecific example, the product is water insoluble, or by the use of typical medium may contain: sucrose, 5-10%, specific p c p a g agents peptone, 0.1%, dipotassium phosphate 0.2% and If, however, the polysaccharide is not removed sodium chloride 0.1%. The pH of the medium from the culture solution before esterification preferably is adjusted to slightly on the alkaline or etherification, the product obtained is a mixside of neutrality. v

The production of the polysaccharide is favored by keeping the reaction of the media slightly alkaline throughout the period of fermentation. This may be accomplished by the ture of compounds. It will contain, besides the ethers and/or esters of the polysaccharide, the corresponding derivatives of any excess sucrose or metabolic products remaining in the fermented culture media. In some cases this may be desirable since a blending of these various derivatives yields a product with a range of so]- ubilities. However, in cases in which a product with the specific properties of the polysaccharide derivative alone is desired, it is necessary either to separate the'dextrans or levans from the culture media before chemical treatment, or else to remove the undesirable by-products, from the mixture obtained by the direct treatment of the fermented media, by the use of sps'aciflc solvents.

Whether the fermented media are treated directly, or the polysaccharides first isolated by alcohol or acetone precipitation, the proportions of the reactants used in the: preparation of the ether derivatives are approximately as follows: one mol of the polysaccharide, 3.5 mols of the alkyl or aralkyl halide and 4.5 mols of sodium hydroxide. If the polysaccharide was isolated from the medium before the chemical treatment, sumcient water must be added to the mixture so as to yield approximately a per cent solution of the sodium hydroxide.

If the fermented culture medium itself is used, the amount of water present should be so regulated by concentration or dilution to againyield approximately a 10 percent solution of the alkali. After addition of the reagents the mixture is heated for a predetermined time, usually 4 to 6 hours, at a temperature anywhere from 80 to 130 degrees C. This temperature depends on the derivative being prepared.

In general, the higher the temperature and the longer the period of heating the greater will be the number of hydroxyl groups in the polysaccharide which will be substituted by the organic radical of the halide compound used. The temperature and time of heating employed is consequently governed by the type of product desired. The organic halide used may be any member of the aliphatic series such as methyl chloride, ethyl chloride, propyl or isopropyl chloride, butyl chloride or any of its isomers. etc., or any one of the araliphatic series such as benzyl chloride.

The aliphatic derivatives are water soluble, at least as high as the butyl derivative. The benzyl ethers are generally water insoluble. Regardless of the type of organic halide used, increasing the proportion of halide to polysaccharide, running the reaction at a higher temperature and for a longer period of time will generally result in a decreased water solubility for the products obtained.

It is to be understood that the organic halide used may be either the chloride, bromide or iodide derivative. For purposes of economy, the chlorides are generally employed.

At the conclusion of the reaction period excess halide is recovered by any suitable process such as steam distillation. The product is isolated by mechanical means if it is water insoluble or by precipitation if it is water soluble.

The process may be varied by the simultaneous introduction of two or more organic halide compounds into the reaction mixture, in which case the product will be a mixed ether; or a particular ether derivative may be prepared and the product fromthe reaction then treated with a difierent organic halide to yield a mixed ether derivative. Again, an ether derivative may be prepared and then further treated with organic acid chlorides, acid anhydrides and the like for the preparation of mixed ether-ester derivatives. Such variations in treatment are, of course, almost without number.

' chloride and 40 gm. of sodium hydroxide.

The products in general are to be described as plastic, amorphous masses, either water soluble or insoluble depending upon the reaction conditions and the particular halide employed. As an example, the benzyl ether of dextran is a water insoluble material which resists the action of the common organic solvents, while the butyl ether of dextran is water soluble. V

The following are examples of specific practices of our method for the production of new products. It will be understood we do not desire to be confined to the detailed proportions, temperatures and pressures, although we are recitlng hereinafter those that we have found to be the preferred temperatures and other conditions.

It will be further understood that it is comprehended within this process the production of a large number of allied materials.

It will be further understood that we are illustrating the process and the materials that can be produced by typical materials within which we comprehend other similar new materials.

* EXAMPLE I Benzyl ether derivatives This process may be carried out directly on the fermented culture media containing the polysaccharide, "such as dextran, although the same process can be employed with the extracted dextran after it has been removed from the culture media. This'statement applies to the other examples hereinafter recited.

To a portion of the fermented culture medium in which the polysaccharide has been produced and in which there is approximately 30 gm. of the polysaccharide, is added 90 gm. of benzyl The resulting mixture is heated for approximately flve hours. If the temperature is held at to degrees C., the crude product is light orange in color and soft and rubberyin consistency. When higher temperatures of from to degrees C. are employed, an orange-brown product is obtained of the same consistency but of greater resistance to solvents. The time of heating may range from 4 to 6 hours but 5 hours is the preferable time. By varying the temperature of this benzyl'ation process, the solubilities in various solvents of the resulting products are varied. These products are substantially insoluble in water.

EXAMPLE II Butyl ether derivatives To a portion of the fermented culture medium containing 30 gm. of dextran, we add gm. of butyl chloride and 40 gm. of sodium hydroxide. The mixture is heated at 100 degrees C. for four hours. The derivative is an amorphous mass that is water soluble.

EXAMPLE III Mixed benzyl ether-butyl ether derivatives To a water solution of the butyl ether derivative is added benzyl chloride and sodium hydroxide in the proportion of 30 gm. of the butyl ether; 90 gm. of benzyl chloride and 40 gm. of sodium hydroxide. The mixture is heated at 80 to 85 degrees C. for a period of five hours. After removal of excess benzyl chloride and benzyl alcohol by steam distillation, the resulting product is isolated as a rather firm and leathery amorphous mass. 7

EXAMPLE IV Beta-hydroxy ethyl ether derivatives To a volume of the fermented culture medium containing about 30 gm. of dextran was added 160 EXAMPLE V Mixed beta-hydroxy ethyl ether-benzyl ether derivatives To a. water solution of the beta-hydroxy ethyl ether derivative was added benzyl chloride and sodium hydroxide in the proportion 30 gm. of the ether, 90 gm. of benzyl chloride and 40 gm. of alkali. The mixture was heated at 80 to 85 degrees C. for five hours. After removal of excess benzyl chloride and benzyl alcohol by steam distillation, the resulting product appeared as a golden-brown, rather moist and stringy amorphous mass.

This application is a division of our co-pending application Serial No. 156,426, filed July 29, 1937.

It will be understood that we desire to comprehend within this invention such modifications as come within the scope of our claim and our invention.

It will be understood that the temperatures and times are relative and may be varied within reasonable limits to secure the objectives desired.

Having thus fully described our invention, what we claim as new and desire to secure by Letters Patent is:

A method of making mixed benzyl ether-butyl ethers of dextran, comprising adding benzyl chloride and sodium hydroxide to a water solution of dextran butyl ether in the proportion of gms. of dextran butyl ether, 90 gms. of benzyl chloride and gms. of sodium hydroxide, heating the mixture at to C. for a period of about 5 hours, and removing the excess benzyl chloride and benzyl alcohol by heating.

GRANT L. STAHLY. WARNER W. CARISON. 

